1 Influence of lightweight aggregates on the physical and mechanical residual properties of concrete subjected to high temperatures Roufael Georges (1) , Beaucour Anne-lise (1) , Eslami Javad (1) , Hoxha Dashnor (2) , Noumowe Albert (1) (1) CY Cergy Paris Université, Laboratoire de Mécanique et Matériaux du Génie Civil, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise Cedex, France (2) Université d’Orléans, Université de Tours, INSA Centre Val de Loire Laboratoire de Mécanique Gabriel Lamé Polytech Orléans, 8 rue Léonard de Vinci, 45072 Orléans, France ABSTRACT 1 This research studies the high temperature behavior of lightweight aggregate concretes (LWAC) by 2 providing a comprehensive study that regroups the physical, thermo-mechanical and mechanical 3 properties of three different LWACs. Then these properties are compared to the properties of a 4 normal-weight concrete (NWC) as well as to those of the mortar phase of these concretes, thus, 5 enabling us to isolate and identify specific behaviors of the lightweight aggregates (LWA). Contrary to 6 the normal weight aggregates, the LWAs showed a compatibility in thermal strain with the mortar 7 phase, which led to fewer cracks in the interfacial transition zone (ITZ) and thus, it resulted in a 8 divergence in behavior between LWACs and NWC, particularly for the residual permeability and 9 tensile strength values. While LWACs generally exhibited lower decrease of failure strengths, and 10 Young Modulus with temperature than NWCs, its Poisson’s ratio was greatly decreased after 300°C. 11 Keywords: Lightweight Concrete, Expanded clay aggregate, Expanded shale aggregate, High 12 Temperature, Thermal deformation, Residual mechanical properties, 13 1 INTRODUCTION 14 The first lightweight aggregates (LWA) used in construction by the Romans were natural aggregates 15 derived from volcanic rocks, such as pumice. Today, lightweight aggregates can be manufactured 16 using natural raw materials such as clay, shale and slate [1], [2]. Due to its low density, lightweight 17 aggregate concrete (LWAC) is used in the construction of stadiums, long span bridges and even 18 offshore platforms. On the other hand, and in order to meet the environmental challenges of the 21st 19 century and the increasingly demanding thermal regulations like the French standards (RT 2012 & RT 20 2020), the structural lightweight concrete is being used to improve the energy efficiency in buildings. 21 It can reduce heating energy needs up to 15%, by replacing traditional structural concrete [3]. This 22 research work is a continuation of the work of [4] and [5] conducted at the Laboratory of Mechanics 23 and Materials of Civil Engineering of CY Cergy Paris Université. It focuses on the behavior at high 24 temperature of structural lightweight aggregate concretes, especially LWAC made of expanded clay 25 and shale aggregates, in order to ensure a safer design of buildings regarding fire. The fire resistance 26 © 2020 published by Elsevier. This manuscript is made available under the CC BY NC user license https://creativecommons.org/licenses/by-nc/4.0/ Version of Record: https://www.sciencedirect.com/science/article/pii/S0950061820332256 Manuscript_13e2a637563bfd2a55082493fd3bf048
Influence of lightweight aggregates on the physical and mechanical residual properties of concrete subjected to high temperatures
Apr 22, 2023
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